New Bremen
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the New Bremen clear sky chart from 2005-11-06 to 2025-01-22.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.

Observation Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(no limit)	Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

By Month

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

		Occurrence of each Forecast	Data Points
Cloud Cover	Day	14% 10% 4 8% 5% 4 4 4 6% 7% 34%	105244
	Night	15% 11% 4 8% 5% 4 4 3 5% 6% 34%	104129
Transparency	Day	47% 6% 12% 21% 13% 1	108900
	Night	48% 6% 11% 21% 13% 2	108613
Seeing	Day	18% 10% 26% 24% 15% 7%	15742
	Night	19% 9% 28% 28% 14% 2	25628

By Month

Percentage Cloud Cover SE (2006-)
Color Meanings: Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	17% 17% 9% 13% 6% 4 4 2 4 5% 19%	2607
	11th to 20th	Day	16% 18% 7% 12% 6% 5% 8% 5% 4 4 15%	2643
	21st to end	Day	27% 20% 9% 12% 5% 3 3 2 3 4 12%	3133
February	1st to 10th	Day	18% 17% 6% 12% 6% 5% 4 2 5% 5% 21%	1769
	11th to 20th	Day	15% 12% 5% 14% 7% 4 5% 3 4 5% 25%	1848
	21st to end	Day	16% 16% 4 9% 5% 5% 4 3 4 7% 27%	1570
March	1st to 10th	Day	21% 19% 5% 9% 4 4 4 3 3 5% 22%	3142
	11th to 20th	Day	13% 10% 3 7% 5% 4 5% 4 6% 7% 37%	3480
	21st to end	Day	19% 11% 4 10% 5% 5% 4 4 5% 6% 28%	3815
April	1st to 10th	Day	14% 11% 4 10% 6% 5% 4 4 5% 6% 31%	2251
	11th to 20th	Day	18% 8% 3 7% 5% 5% 4 4 5% 7% 35%	2329
	21st to end	Day	19% 9% 3 8% 5% 5% 4 4 5% 8% 31%	2470
May	1st to 10th	Day	20% 10% 3 8% 5% 5% 5% 3 6% 7% 29%	4082
	11th to 20th	Day	20% 7% 2 5% 4 4 5% 4 6% 7% 37%	4081
	21st to end	Day	9% 6% 2 7% 5% 5% 5% 4 8% 10% 37%	4476
June	1st to 10th	Day	13% 6% 2 6% 5% 5% 5% 4 7% 8% 40%	2576
	11th to 20th	Day	10% 5% 2 6% 5% 4 6% 4 7% 10% 42%	2660
	21st to end	Day	9% 5% 2 6% 5% 4 6% 6% 8% 10% 38%	2660
July	1st to 10th	Day	12% 7% 2 7% 5% 4 5% 5% 7% 11% 35%	4440
	11th to 20th	Day	7% 4 2 5% 4 4 4 4 7% 12% 46%	4440
	21st to end	Day	8% 6% 3 7% 5% 5% 6% 5% 7% 10% 38%	4466
August	1st to 10th	Day	8% 6% 2 6% 4 4 4 4 8% 10% 44%	4104
	11th to 20th	Day	8% 5% 2 6% 4 5% 5% 5% 8% 10% 43%	4044
	21st to end	Day	7% 5% 2 6% 4 4 4 4 7% 11% 46%	4279
September	1st to 10th	Day	11% 6% 2 5% 5% 4 4 3 5% 7% 48%	2171
	11th to 20th	Day	9% 5% 2 6% 5% 4 4 4 7% 9% 45%	2090
	21st to end	Day	17% 7% 2 6% 4 4 3 3 4 6% 44%	2090
October	1st to 10th	Day	12% 6% 3 7% 4 4 4 3 5% 7% 45%	2090
	11th to 20th	Day	15% 7% 2 6% 4 4 4 4 5% 7% 42%	1914
	21st to end	Day	19% 9% 3 8% 4 4 4 4 6% 7% 31%	1921
November	1st to 10th	Day	10% 8% 3 6% 3 3 4 3 5% 6% 49%	1762
	11th to 20th	Day	17% 13% 4 9% 5% 4 4 3 5% 5% 33%	1800
	21st to end	Day	18% 15% 5% 9% 4 4 3 3 5% 5% 29%	1800
December	1st to 10th	Day	15% 14% 5% 9% 5% 5% 4 3 5% 5% 30%	2930
	11th to 20th	Day	17% 16% 6% 12% 6% 4 5% 4 5% 4 22%	3329
	21st to end	Day	22% 20% 8% 12% 6% 5% 4 3 3 4 13%	3982
January	1st to 10th	Night	17% 17% 8% 14% 5% 4 3 3 4 4 20%	4568
	11th to 20th	Night	14% 19% 9% 15% 6% 5% 5% 4 4 3 15%	4542
	21st to end	Night	27% 19% 7% 9% 4 4 3 3 3 4 16%	4546
February	1st to 10th	Night	21% 14% 5% 9% 6% 5% 4 3 4 5% 25%	2409
	11th to 20th	Night	13% 14% 5% 10% 6% 5% 4 3 5% 6% 29%	2218
	21st to end	Night	20% 13% 5% 10% 5% 5% 3 3 5% 5% 26%	1884
March	1st to 10th	Night	20% 14% 4 7% 4 4 3 2 4 5% 34%	3711
	11th to 20th	Night	12% 8% 3 6% 4 4 4 4 5% 7% 44%	3480
	21st to end	Night	18% 10% 4 7% 5% 4 4 2 4 5% 37%	3817
April	1st to 10th	Night	16% 10% 3 6% 5% 4 4 4 5% 7% 36%	1945
	11th to 20th	Night	17% 8% 2 7% 5% 4 5% 3 5% 8% 37%	1798
	21st to end	Night	18% 8% 3 7% 5% 4 4 3 6% 6% 36%	1710
May	1st to 10th	Night	19% 11% 4 8% 5% 4 5% 4 5% 7% 29%	2813
	11th to 20th	Night	19% 8% 2 5% 5% 3 4 3 6% 8% 37%	2812
	21st to end	Night	10% 6% 2 5% 4 5% 5% 4 7% 10% 43%	3079
June	1st to 10th	Night	8% 6% 3 6% 4 4 4 4 5% 9% 47%	1598
	11th to 20th	Night	9% 5% 2 5% 4 5% 4 5% 5% 10% 47%	1520
	21st to end	Night	8% 6% 2 5% 5% 4 4 4 6% 10% 45%	1520
July	1st to 10th	Night	10% 5% 2 6% 4 5% 5% 4 5% 9% 45%	2530
	11th to 20th	Night	6% 4 2 4 4 4 4 4 7% 10% 52%	2530
	21st to end	Night	10% 6% 2 6% 5% 5% 5% 3 7% 9% 43%	3085
August	1st to 10th	Night	11% 7% 2 7% 4 4 5% 4 6% 8% 41%	2825
	11th to 20th	Night	7% 6% 3 6% 4 4 4 4 7% 8% 47%	2785
	21st to end	Night	5% 4 2 6% 5% 5% 5% 4 6% 8% 50%	3373
September	1st to 10th	Night	11% 5% 3 5% 3 3 4 3 5% 7% 51%	1989
	11th to 20th	Night	9% 6% 1 4 3 3 3 3 5% 7% 56%	2090
	21st to end	Night	12% 7% 2 6% 4 4 4 4 5% 6% 46%	2090
October	1st to 10th	Night	10% 5% 2 6% 3 3 3 3 5% 7% 51%	2090
	11th to 20th	Night	16% 8% 3 7% 4 4 3 3 4 7% 40%	2266
	21st to end	Night	19% 7% 2 7% 4 4 4 4 5% 6% 37%	2674
November	1st to 10th	Night	13% 9% 2 5% 4 3 3 3 5% 6% 46%	2536
	11th to 20th	Night	15% 12% 4 8% 4 4 4 3 6% 5% 35%	2600
	21st to end	Night	18% 14% 4 9% 6% 4 4 4 4 5% 27%	2600
December	1st to 10th	Night	14% 11% 4 9% 6% 5% 5% 5% 5% 7% 28%	4250
	11th to 20th	Night	18% 17% 8% 12% 5% 4 4 3 4 4 21%	4850
	21st to end	Night	23% 20% 7% 11% 5% 4 4 3 4 5% 14%	6996

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	67% 4 7% 13% 8%	2608
	11th to 20th	Day	72% 4 10% 8% 6%	2643
	21st to end	Day	78% 3 7% 8% 3	3133
February	1st to 10th	Day	66% 4 10% 12% 8% 1	1769
	11th to 20th	Day	61% 4 10% 17% 7% 1	1858
	21st to end	Day	58% 5% 11% 16% 8% 2	1570
March	1st to 10th	Day	64% 5% 9% 15% 6%	3142
	11th to 20th	Day	45% 6% 10% 27% 11% 1	3480
	21st to end	Day	56% 6% 13% 19% 5%	3815
April	1st to 10th	Day	53% 6% 11% 18% 12%	2251
	11th to 20th	Day	47% 6% 12% 20% 12% 2	2329
	21st to end	Day	51% 7% 12% 18% 11% 2	2470
May	1st to 10th	Day	52% 8% 11% 20% 9% 1	4120
	11th to 20th	Day	45% 7% 14% 24% 9% 1	4085
	21st to end	Day	37% 11% 13% 22% 16% 2	4489
June	1st to 10th	Day	40% 7% 11% 24% 15% 2	2576
	11th to 20th	Day	36% 8% 13% 25% 16% 2	2660
	21st to end	Day	38% 9% 14% 21% 14% 4	2660
July	1st to 10th	Day	42% 7% 12% 22% 16% 2	4371
	11th to 20th	Day	29% 8% 14% 27% 21% 1	4365
	21st to end	Day	39% 8% 14% 19% 17% 3	4324
August	1st to 10th	Day	32% 8% 18% 27% 14% 1	4091
	11th to 20th	Day	33% 7% 12% 32% 15% 1	4083
	21st to end	Day	31% 7% 14% 31% 14% 3	4278
September	1st to 10th	Day	36% 7% 11% 21% 20% 4	2171
	11th to 20th	Day	34% 8% 10% 24% 22% 3	2090
	21st to end	Day	41% 5% 10% 22% 21% 1	2090
October	1st to 10th	Day	26% 5% 11% 31% 26% 1	3480
	11th to 20th	Day	32% 5% 12% 25% 24% 1	3154
	21st to end	Day	42% 4 10% 24% 19% 1	3145
November	1st to 10th	Day	36% 5% 12% 26% 19% 2	1762
	11th to 20th	Day	53% 4 9% 20% 11% 3	1800
	21st to end	Day	58% 5% 10% 18% 8% 1	1800
December	1st to 10th	Day	54% 4 15% 20% 7%	2930
	11th to 20th	Day	64% 4 13% 14% 5%	3326
	21st to end	Day	76% 3 7% 9% 4	3982
January	1st to 10th	Night	67% 5% 9% 13% 6%	4568
	11th to 20th	Night	73% 4 7% 11% 4	4542
	21st to end	Night	72% 4 8% 11% 4	4546
February	1st to 10th	Night	62% 5% 10% 14% 8% 1	2409
	11th to 20th	Night	56% 5% 11% 16% 11% 1	2219
	21st to end	Night	60% 5% 10% 15% 9% 2	1884
March	1st to 10th	Night	54% 4 8% 24% 10% 1	3711
	11th to 20th	Night	38% 7% 13% 27% 14% 2	3480
	21st to end	Night	49% 5% 11% 26% 9% 1	3817
April	1st to 10th	Night	46% 6% 12% 20% 14% 1	1945
	11th to 20th	Night	44% 8% 10% 18% 16% 3	1798
	21st to end	Night	48% 6% 10% 20% 13% 3	1710
May	1st to 10th	Night	53% 8% 9% 20% 9% 2	2840
	11th to 20th	Night	43% 8% 13% 26% 10% 1	2813
	21st to end	Night	32% 10% 14% 25% 16% 3	3087
June	1st to 10th	Night	33% 7% 11% 25% 21% 3	1598
	11th to 20th	Night	32% 8% 12% 26% 18% 3	1520
	21st to end	Night	33% 8% 15% 24% 17% 4	1520
July	1st to 10th	Night	36% 7% 11% 25% 16% 6%	2490
	11th to 20th	Night	27% 7% 15% 29% 21% 1	2482
	21st to end	Night	37% 6% 16% 19% 18% 5%	2987
August	1st to 10th	Night	39% 8% 13% 25% 14% 1	2814
	11th to 20th	Night	33% 7% 11% 31% 18% 1	2812
	21st to end	Night	31% 8% 13% 26% 19% 3	3373
September	1st to 10th	Night	33% 6% 12% 25% 19% 5%	1989
	11th to 20th	Night	29% 5% 9% 28% 26% 3	2090
	21st to end	Night	36% 7% 10% 22% 22% 2	2090
October	1st to 10th	Night	23% 4 8% 31% 33% 2	3480
	11th to 20th	Night	33% 4 11% 26% 25% 1	3765
	21st to end	Night	35% 4 8% 29% 22% 3	4400
November	1st to 10th	Night	39% 4 11% 24% 20% 2	2536
	11th to 20th	Night	49% 5% 9% 20% 14% 3	2600
	21st to end	Night	59% 5% 10% 18% 7% 1	2600
December	1st to 10th	Night	54% 4 12% 22% 7%	4250
	11th to 20th	Night	66% 4 11% 12% 7%	4852
	21st to end	Night	73% 5% 9% 10% 3	6996

Seeing (when cloud cover <= 80%)
Color Meanings: Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	24% 20% 32% 19% 4	300
	11th to 20th	Day	26% 17% 38% 14% 4 1	300
	21st to end	Day	34% 16% 29% 16% 5%	300
February	1st to 10th	Day	31% 16% 32% 17% 3	270
	11th to 20th	Day	25% 19% 37% 13% 6%	270
	21st to end	Day	24% 17% 44% 14% 1	225
March	1st to 10th	Day	25% 18% 37% 17% 3	279
	11th to 20th	Day	26% 12% 32% 23% 6% 1	460
	21st to end	Day	30% 15% 28% 20% 6%	506
April	1st to 10th	Day	18% 19% 31% 21% 9% 2	460
	11th to 20th	Day	21% 18% 27% 21% 9% 4	452
	21st to end	Day	22% 12% 33% 21% 8% 2	460
May	1st to 10th	Day	24% 10% 34% 21% 8% 3	463
	11th to 20th	Day	23% 8% 25% 24% 13% 8%	487
	21st to end	Day	11% 7% 26% 28% 19% 10%	529
June	1st to 10th	Day	14% 6% 24% 32% 18% 7%	596
	11th to 20th	Day	10% 6% 23% 31% 22% 7%	680
	21st to end	Day	12% 5% 27% 28% 20% 8%	680
July	1st to 10th	Day	11% 3 18% 27% 22% 19%	671
	11th to 20th	Day	7% 4 20% 30% 25% 14%	668
	21st to end	Day	10% 2 17% 27% 27% 16%	532
August	1st to 10th	Day	9% 4 14% 25% 31% 16%	486
	11th to 20th	Day	12% 2 18% 30% 25% 13%	479
	21st to end	Day	9% 3 13% 28% 33% 14%	539
September	1st to 10th	Day	13% 4 14% 26% 30% 12%	490
	11th to 20th	Day	9% 2 13% 28% 31% 17%	490
	21st to end	Day	20% 9% 21% 21% 19% 9%	490
October	1st to 10th	Day	12% 6% 24% 30% 17% 12%	490
	11th to 20th	Day	17% 13% 31% 23% 13% 3	490
	21st to end	Day	27% 11% 34% 23% 5% 1	370
November	1st to 10th	Day	15% 15% 36% 21% 9% 4	300
	11th to 20th	Day	25% 15% 31% 18% 10% 1	300
	21st to end	Day	28% 12% 41% 16% 3	300
December	1st to 10th	Day	21% 20% 36% 16% 6% 1	300
	11th to 20th	Day	22% 16% 42% 16% 4	300
	21st to end	Day	29% 19% 32% 16% 3	330
January	1st to 10th	Night	25% 15% 36% 19% 5%	1000
	11th to 20th	Night	26% 15% 37% 17% 5%	975
	21st to end	Night	25% 13% 35% 23% 4	841
February	1st to 10th	Night	26% 11% 34% 25% 3	760
	11th to 20th	Night	21% 14% 38% 25% 2	743
	21st to end	Night	27% 13% 37% 21% 3	628
March	1st to 10th	Night	21% 13% 34% 24% 7% 1	760
	11th to 20th	Night	18% 15% 34% 26% 6% 1	760
	21st to end	Night	23% 13% 29% 26% 8%	836
April	1st to 10th	Night	20% 11% 33% 29% 5% 1	615
	11th to 20th	Night	21% 10% 31% 27% 9% 1	563
	21st to end	Night	21% 9% 35% 25% 9% 1	570
May	1st to 10th	Night	22% 8% 33% 27% 10% 1	570
	11th to 20th	Night	22% 4 26% 30% 16% 2	561
	21st to end	Night	9% 4 23% 37% 25% 3	617
June	1st to 10th	Night	10% 2 24% 42% 21% 1	570
	11th to 20th	Night	12% 3 21% 40% 24% 1	570
	21st to end	Night	9% 3 24% 36% 27% 2	570
July	1st to 10th	Night	11% 1 15% 37% 30% 6%	555
	11th to 20th	Night	8% 2 17% 39% 29% 5%	552
	21st to end	Night	10% 2 12% 41% 34% 2	624
August	1st to 10th	Night	9% 2 10% 41% 33% 4	567
	11th to 20th	Night	8% 2 12% 40% 33% 5%	564
	21st to end	Night	8% 2 11% 35% 38% 5%	627
September	1st to 10th	Night	12% 4 15% 34% 30% 4	659
	11th to 20th	Night	12% 3 13% 33% 34% 5%	760
	21st to end	Night	14% 5% 23% 31% 23% 3	760
October	1st to 10th	Night	13% 4 24% 34% 20% 4	760
	11th to 20th	Night	21% 11% 27% 27% 13%	760
	21st to end	Night	22% 11% 32% 26% 8%	836
November	1st to 10th	Night	18% 9% 33% 26% 13% 1	780
	11th to 20th	Night	21% 15% 32% 25% 6% 1	800
	21st to end	Night	24% 14% 31% 25% 6%	800
December	1st to 10th	Night	25% 14% 33% 22% 5%	800
	11th to 20th	Night	26% 13% 34% 22% 5%	815
	21st to end	Night	30% 14% 32% 20% 3	1100

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